Random Access Memory9

 

Random Access Memory

 

RAM is Random Access Memory. RAM is the place where your computer stores programs that you are currently sprinting and data that you are currently working on.

RAM can be contrasted with disk cache. Disk cache holds entire of your procedures and all of your data -- whether you are working with them or not. When you corner off your computer, the contents of RAM immediately evaporate, but the contents of your disk storage remain unharmed.

RAM is also periodically contrasted with ROM. ROM (Read Only Memory) are memory chips which have had information cached on them which cannot be changed.

 

How big is RAM?

RAM is small, both in physical size (it's stored in microchips) and in the amount of data it can hold. It's much smaller than your hard disk. A typical computer may come with 256 million bytes of RAM and a hard disk that can hold 40 billion bytes. RAM comes in the form of "discrete" (meaning separate) microchips and also in the form of modules that plug into chasms in the computer's motherboard. These holes connect through a bus or set of electrical routes to the processor. The hard steer, on the other hand, stores data on a magnetized surface that looks like a phonograph disc.

Most private computers are designed to grant you to multiplication annexed RAM modules up to a definite restrict. Having more RAM in your computer reduces the number of times namely the computer processor has to read data in from your hard disk, an operation that takes much longer than reading data from RAM. (RAM access time is in nanoseconds; hard disk access time is in milliseconds.)

 

Types of RAM

 

The following are some common types of RAM:

• SRAM: Static random access memory uses multiple transistors, typically four to six, for every memory cell but doesn't have a capacitor in each cell. It is accustomed mainly for cache.










• DRAM: Dynamic random access memory has memories compartments with a coupled transistor and capacitor requiring constant activating.










• FPM DRAM: Fast sheet mode dynamic random access memory was the native manner of DRAM. It waits via the entire process of locating a morsel of data by col and row and then reading the morsel ahead it starts aboard the afterward bit. Maximum transmit rate to L2 store is nearly 176 MBps.










• EDO DRAM: Extended data-out dynamic irregular way memory does not await for all of the processing of the 1st bit before chronic to the next 1. As soon as the residence of the first bit is situated, EDO DRAM begins seeing for the next bit. It is about five percent faster than FPM. Maximum transfer rate to L2 cache is approximately 264 MBps.










• SDRAM: Synchronous dynamic random access memory takes convenience of the explode mode notion to greatly cultivate performance. It does this by lingering on the row including the requested bit and moving rapidly through the columns, reading each bit for it goes. The motif is that most of the period the data needed by the CPU will be in series. SDRAM is almost five percentage faster than EDO RAM and is the most common form in desktops today. Maximum transfer rate to L2 cache is approximately 528 MBps.










• DDR SDRAM: Double data rate synchronous dynamic RAM is just like SDRAM besides that is has higher bandwidth, meaning greater speed. Maximum transfer rate to L2 cache is approximately 1,064 MBps (for DDR SDRAM 133 MHZ).










• RDRAM: Rambus dynamic random access memory namely a radical departure from the before DRAM structure. Designed by Rambus , RDRAM uses a Rambus in-line memory module (RIMM), which is similar in size and needle configuration apt a criterion DIMM. What makes RDRAM so assorted is its use of a special high-speed file bus cried the Rambus channel. RDRAM memories pieces go in parallel to achieve a file rate of 800 MHz, or 1,600 MBps. Since they manipulate at such tall speeds, they generate many extra heat than additional types of chips. To aid dissipate the excess heat Rambus chips are fitted with a heat spreader, which looks like a long slender layer. Just favor there are smaller versions of DIMMs, there are also SO-RIMMs, designed because notebook computers.










• Credit Card Memory: Credit card memory is a proprietary self-contained DRAM memory module that plugs into a special slot for use in notebook computers.










• PCMCIA Memory Card: Another self-contained DRAM module for notebooks, cards of this type are not proprietary and ought work with whichever notebook computer whose system bus matches the memory card's configuration.










• CMOS RAM: CMOS RAM is a term for the small quantity of memory used by your computer and some other devices to memorize entities like hard disk settings -- penetrate Why does my computer absence a power cell? For details. This memory uses a small battery to invest it with the power it needs to preserve the memory contents.










• VRAM: Video RAM, also known as multiport dynamic random access memory (MPDRAM), is a type of RAM used specifically for video adapters or 3-D accelerators. The "multiport" portion comes from the truth that VRAM usually has two neutral access ports instead of one, allowing the CPU and graphics processor to access the RAM simultaneously. VRAM is located on the graphics card and comes in a kind of formats, many of which are proprietary. The amount of VRAM is a determining element in the resolution and color depth of the display. VRAM is also used to prop graphics-specific information such as 3-D geometry data and texture maps. True multiport VRAM tends to be expensive, so today, numerous graphics cards use SGRAM (synchronous graphics RAM) instead. Performance is nearly the same, but SGRAM is cheaper.